Victorians have a right to cast a critical eye over Premier Daniel Andrews' $6.7 billion West Gate Tunnel, which delivers a decade more of tolls for Transurban on the lucrative CityLink.

There is little doubt that Melbourne needs a second major road link to the western suburbs and beyond — the suburbs are booming and road freight needs an alternative to the West Gate bridge.

But it is a big political risk to be slugging road users an extra 10 years of increased tolls on CityLink to pay for it, boosting Transurban's bottom line.

How the State Government got to the point of signing a contract — dreamt up by Transurban not state planners — deserves scrutiny and makes Labor vulnerable to the accusation of sweetheart deals with private business.

Taxpayers now look likely to fork out billions more because the toll extension plan will be blocked in this Parliament.

The Government is under no obligation to put the extension through before the election.

But it sets the battle lines for a campaign on toll-funded versus taxpayer-funded roads.

Far cry from Labor's election platform

The $6.7 billion contract signed this week is a far cry from Labor's 2014 election pitch.

What does the deal involve?

$6.7 billion project — Transurban to pay $4 billion, the state the rest

Tolls on CityLink will be extended by a decade until 2045, with fees to rise 4.25 per cent annually from 2019 to 2029

The new road will be tolled with an extra fee for cars and light commercial vehicles driving to the city in the morning peak hour, in a move that appears to discourage commuters from driving to work

6,000 new jobs in construction

Work will begin in January and finish by 2022, at the end of the next term of government

Compensation for Transurban for when the state builds other road projects has been scrapped

If the toll extension is not agreed to by Parliament, which is a real possibility, the state will cover the shortfall

At the most recent state poll Labor told voters it would build a $500 million West Gate Distributor, promising the shovel-ready project could be built quickly and take trucks off streets of the inner-west.

At the same time, it was railing against the Napthine Government's East West Link, arguing it was a waste of money and did not stack up — something critics of this new project argue.

It also argued the Coalition were not transparent about the project and that it had no mandate to sign contracts for East West. Sound familiar?

Labor ultimately dumped the project, costing taxpayers more than $1 billion, despite assurances it would not cost a cent.

Less than six months into its term of government, Labor received an "unsolicited" proposal from Transurban to build a much grander road project to the west to ease congestion.

At the cost of $5.5 billion the company was going to fund most of it through a proposal to extend tolls on CityLink.

Ever since that decision to follow through on the election pledge to tear up East West Link, Labor has needed a road project to fill the abyss created by scrapping the project.

Tackling congestion is a high priority for many voters, and Labor will be hoping the West Gate Tunnel, along with local measures like level crossing removals, will ease voter concerns.

It should be noted the long-term vision for the East West Link — once the section from Clifton Hill to Parkville (through politically sensitive inner-city seats) was built — was a second section to be built from the city to the western ring road.

Perhaps if the western section was built first in a less politically sensitive area and one of obvious need, Victorians wouldn't again be caught in a political fight over infrastructure.

The post-Northcote world

Since Labor's thumping in the Northcote byelection at the hands of the Greens, Labor has talked about getting back to "bread and butter" issues.

And since the November 18 smashing Premier Andrews has outlined more than $22 billion for road projects; the West Gate Tunnel and the North-East Link.